Absence of Event = Event

Link: http://feedproxy.google.com/~r/ElementalLinks/~3/JN-Vm0OuUrI/

From Elemental Links

In this week’s Active Information post, I riff off a quote by Jud Valeski the CEO of Gnip, on the dearth of event-driven talent:

“Beyond infrastructure issues, as engineers, the web app programming we’ve been doing over the past 15 years has taught us to build applications in a highly synchronous transactional manner…”

“…You would be shocked at the ratio of engineers who can’t build event-driven, asynchronous data processing applications, to those who can, yet this is a big part of this space.”

If you are a frequent reader here, you’ve seen the event constructs I published over there.

One that I didn’t include is the fact that the absence of an event can be an event.  Chris Martins brought that up on Twitter.

In my initial event writing, I wrote of a system heartbeat example:

“…a business-to-business order gateway is supposed to be emitting System Heartbeat events every 15 minutes. The System Heartbeat events inform IT operations the gateway is up and running. The absence of a heartbeat event indicates a failure. If the order gateway is down, business customers are likely to place an order with a competitor.”

On Twitter yesterday, I mentioned an event-driven billing subsystem I’m currently working on.  In that system, we’ll be generating a (standard) projected monthly invoice.  The invoice generation starts when the party is approved for billing.

Invoice regeneration is triggered by a set of events, including a change in plan, the receipt of a payment, or the absence of the receipt of payment.  In this subsystem, the absence of a receipt is a non-payment event.

So, yes.  The absence of an event is absolutely an event.

Related posts:

  1. 5th Anniversary Edition – Event-Driven Architecture Overview
  2. BBC Business News: Real-time (Event Processing) beyond Wall Street
  3. In-brief: Conversation with Jeff Wootton on Event Processing at Sybase, SAP Company